1. Field of the Invention
The present invention relates, in general, to collapsible tent frames capable of making, pitching or striking a tent easily and quickly when necessary and, more particularly, to a collapsible tent frame suitable for giving an enlarged and heightened interior space to users when pitching a tent.
2. Description of the Prior Art
As well known to those skilled in the art, a tent is a collapsible shelter of canvas or other material stretched over and sustained by a frame and is used for camping outdoors or as a temporary structure. It is preferable for such a tent to be easily and quickly pitched or struck when necessary, so a frame for such tents is preferably designed for being collapsible. Examples of typical collapsible tent frames are referred to U.S. Pat. Nos. 4,641,676 (issued on Feb. 10, 1987), 4,779,635 (issued on Oct. 25, 1988), 4,947,884 (issued on Sep. 14, 1990), 5,275,188 (issued on Jan. 4, 1994) and 5,421,356 (issued on Jan. 6, 1995).
The above U.S. patents individually disclose a collapsible tent frame which comprises a plurality of side pole ribs 2, with each pair of ribs 2 being coupled to each other at the center of them into a scissor assembly as shown in FIG. 1. The scissor assemblies of the side pole ribs 2 are also coupled to each other at joints 2a and are connected to four side poles 1 at their outside ends.
In such a case, the outside upper end of each scissor assembly of the ribs 2 is hinged to the top end of a side pole 1, while the outside lower end of each scissor assembly is hinged to a slider 7 movably fitted over the side pole 1. Therefore, when a user moves the four side poles 1 to the center of the tent frame, the sliders 7 move down on the side poles 1 respectively, thus folding the scissor assemblies of the ribs 2 at the joints 2a and collapsing the tent frame.
The above tent frame also comprises a plurality of center pole ribs 3, with each pair of ribs 3 being coupled to each other at the center of them into a scissor assembly. Each scissor assembly of the above ribs 3 is hinged to the joints 2a of the side pole ribs 2 at the outside ends and are hinged to a center pole 6 at the inside ends. In such a case, the inside lower end of each scissor assembly of the ribs 3 is hinged to a connector 4 provided on the lower end of the center pole 6, while the inside upper end of each scissor assembly is hinged to a slide guider 5 into which the center pole 6 is movably fitted. Therefore, when the four side poles 1 are moved to the center of the tent frame, the center pole 6 moves down in the slide guider 5, thus folding the scissor assemblies of the center pole ribs 3 and collapsing the tent frame.
However, the above collapsible tent frame has the following problem. That is, in the above tent frame, the center pole ribs 3 are coupled to the joints 2a of the side pole ribs 2. Therefore, when pitching a tent, the center pole ribs 3 are positioned across the upper portion of the interior space as shown in FIG. 2, thus limiting the height of the interior space.
It is thus necessary for a user to be careful lest one bumps one's head against the center pole ribs 3 or the connector 4 while going out of, coming into or standing in the tent. Therefore, the above tent frame is inconvenient to users.
In addition, the center pole 6 comprises the connector 4 and the slide guider 5, thus having a complex construction and increasing the production cost of the tent frame. Another problem of the above collapsible tent frame resides in that it is too heavy for a user to easily handle or move the frame.